A standard jug has a hollow body shaped to contain a liquid and having a bottom, a top wall, and opposite front and rear walls extending between the bottom and top wall. A collar is formed in and projects upwardly from the top wall adjacent the front wall. This collar defines a pour mouth with which a closure, normally a screw cap, can be sealingly engaged to block this mouth. Some sort of handle is normally provided on the top wall, preferably one that does not project vertically upwardly beyond the plane of the top of the cap so that the jugs can be stacked.
As the jug is tipped forwardly the mouth will normally be lowered below the liquid level in the jug, tapping the air in the jug above the liquid. If no vent is provided to admit air to this region, flow of liquid out of the jug will alternate with flow of air into the jug. Obviously such action means the poured stream is difficult to control so that the user risks making a mess with the liquid. When the liquid is toxic or flammable this can be quite dangerous.
Accordingly it is known to provide a vent on the top wall of the jug adjacent its rear wall. In the simplest plastic jugs a hollow bump is formed that can be broken off to form a vent hole in the top wall. Such an arrangement has the considerable disadvantage that it makes reuse of the jug impossible, and in fact is only used on jugs whose contents are all used at one time, since the vent opening cannot be closed after it has been opened.
Another solution lies in forming a small threaded vent collar on the top wall adjacent the rear wall, and providing a separate screwdown vent cap that can be loosened to permit air to enter the jug. Providing this separate element, the vent cap, and forming the separate threaded opening increases fabrication costs of the jug. In addition it is common for the user to forget to open the vent, exposing himself or herself to the hazards of sloppy pouring mentioned above.
It is possible to provide with a given size jug a vent device that fits over the collar and that has a tube that extends, when it is fitted to the jug, up inside the jug to a location adjacent the rear wall. Thus once this accessory is fitted to the pour mouth air can enter via the tube. Obviously such an accessory is not convenient to use, is liable to get lost, and adds to the cost of the jug.
Finally it has been suggested to combine the handle formation with a vent arrangement. To this end the handle is tubular and has a rear end opening into the body of the jug adjacent its rear wall, and a front end that extends horizontally to the collar where it opens into this collar at the pour mouth. Such an arrangement works quite well for pouring, as air can enter at the uncovered pour mouth into the front handle tube end and pass through the handle to the interior of the jug. The considerable problem with such an arrangement is that the collar must project up above the handle, and the handle structure considerably weakens the jug. Thus stacking such jugs atop one another is impossible.